/*-
* Copyright (c) 1997, 1998, 2005, 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code was contributed to The NetBSD Foundation by Klaus Klein.
* Heavily optimised by David Laight
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

/*
* Inclusion in node-odbc note:
*
* This code was found here: http://social.msdn.microsoft.com/forums/en-US/vcgeneral/thread/25a654f9-b6b6-490a-8f36-c87483bb36b7
* One user posted what looks to be a scaled down version of the NetBSD code
* but did not include any header with their work. Since it seems pretty obvious
* that the user took much of the code from NetBSD, that is why the NetBSD header
* is displayed above.
*/
#include "stdafx.h"
#include "strptime.h"

static int conv_num(const char **, int *, int, int);
static int strncasecmp(char *s1, char *s2, size_t n);

char * strptime(const char *buf, const char *fmt, struct tm *tm)
{
	char c;
	const char *bp;
	size_t len = 0;
	int alt_format, i, split_year = 0;

	bp = buf;

	while ((c = *fmt) != '\0')
	{
		/* Clear `alternate' modifier prior to new conversion. */
		alt_format = 0;

		/* Eat up white-space. */
		if (isspace(c))
		{
			while (isspace(*bp))
				bp++;

			fmt++;
			continue;
		}

		if ((c = *fmt++) != '%')
			goto literal;


	again:    switch (c = *fmt++)
	{
	case '%': /* "%%" is converted to "%". */
		literal :
			if (c != *bp++)
				return (0);
		break;

		/*
		* "Alternative" modifiers. Just set the appropriate flag
		* and start over again.
		*/
	case 'E': /* "%E?" alternative conversion modifier. */
		LEGAL_ALT(0);
		alt_format |= ALT_E;
		goto again;

	case 'O': /* "%O?" alternative conversion modifier. */
		LEGAL_ALT(0);
		alt_format |= ALT_O;
		goto again;

		/*
		* "Complex" conversion rules, implemented through recursion.
		*/
	case 'c': /* Date and time, using the locale's format. */
		LEGAL_ALT(ALT_E);
		if (!(bp = strptime(bp, "%x %X", tm)))
			return (0);
		break;

	case 'D': /* The date as "%m/%d/%y". */
		LEGAL_ALT(0);
		if (!(bp = strptime(bp, "%m/%d/%y", tm)))
			return (0);
		break;

	case 'R': /* The time as "%H:%M". */
		LEGAL_ALT(0);
		if (!(bp = strptime(bp, "%H:%M", tm)))
			return (0);
		break;

	case 'r': /* The time in 12-hour clock representation. */
		LEGAL_ALT(0);
		if (!(bp = strptime(bp, "%I:%M:%S %p", tm)))
			return (0);
		break;

	case 'T': /* The time as "%H:%M:%S". */
		LEGAL_ALT(0);
		if (!(bp = strptime(bp, "%H:%M:%S", tm)))
			return (0);
		break;

	case 'X': /* The time, using the locale's format. */
		LEGAL_ALT(ALT_E);
		if (!(bp = strptime(bp, "%H:%M:%S", tm)))
			return (0);
		break;

	case 'x': /* The date, using the locale's format. */
		LEGAL_ALT(ALT_E);
		if (!(bp = strptime(bp, "%m/%d/%y", tm)))
			return (0);
		break;

		/*
		* "Elementary" conversion rules.
		*/
	case 'A': /* The day of week, using the locale's form. */
	case 'a':
		LEGAL_ALT(0);
		for (i = 0; i < 7; i++)
		{
			/* Full name. */
			len = strlen(day[i]);
			if (strncasecmp((char *)(day[i]), (char *)bp, len) == 0)
				break;

			/* Abbreviated name. */
			len = strlen(abday[i]);
			if (strncasecmp((char *)(abday[i]), (char *)bp, len) == 0)
				break;
		}

		/* Nothing matched. */
		if (i == 7)
			return (0);

		tm->tm_wday = i;
		bp += len;
		break;

	case 'B': /* The month, using the locale's form. */
	case 'b':
	case 'h':
		LEGAL_ALT(0);
		for (i = 0; i < 12; i++)
		{
			/* Full name. */

			len = strlen(mon[i]);
			if (strncasecmp((char *)(mon[i]), (char *)bp, len) == 0)
				break;

			/* Abbreviated name. */
			len = strlen(abmon[i]);
			if (strncasecmp((char *)(abmon[i]), (char *)bp, len) == 0)
				break;
		}

		/* Nothing matched. */
		if (i == 12)
			return (0);

		tm->tm_mon = i;
		bp += len;
		break;

	case 'C': /* The century number. */
		LEGAL_ALT(ALT_E);
		if (!(conv_num(&bp, &i, 0, 99)))
			return (0);

		if (split_year)
		{
			tm->tm_year = (tm->tm_year % 100) + (i * 100);
		}
		else {
			tm->tm_year = i * 100;
			split_year = 1;
		}
		break;

	case 'd': /* The day of month. */
	case 'e':
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &tm->tm_mday, 1, 31)))
			return (0);
		break;

	case 'k': /* The hour (24-hour clock representation). */
		LEGAL_ALT(0);
		/* FALLTHROUGH */
	case 'H':
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &tm->tm_hour, 0, 23)))
			return (0);
		break;

	case 'l': /* The hour (12-hour clock representation). */
		LEGAL_ALT(0);
		/* FALLTHROUGH */
	case 'I':
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &tm->tm_hour, 1, 12)))
			return (0);
		if (tm->tm_hour == 12)
			tm->tm_hour = 0;
		break;

	case 'j': /* The day of year. */
		LEGAL_ALT(0);
		if (!(conv_num(&bp, &i, 1, 366)))
			return (0);
		tm->tm_yday = i - 1;
		break;

	case 'M': /* The minute. */
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &tm->tm_min, 0, 59)))
			return (0);
		break;

	case 'm': /* The month. */
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &i, 1, 12)))
			return (0);
		tm->tm_mon = i - 1;
		break;

	case 'p': /* The locale's equivalent of AM/PM. */
		LEGAL_ALT(0);
		/* AM? */
		if (strncasecmp(const_cast<char*>(am_pm[0]), const_cast<char*>(bp), 2) == 0)
		{
			if (tm->tm_hour > 11)
				return (0);

			bp += strlen(am_pm[0]);
			break;
		}
		/* PM? */
		else if (strncasecmp(const_cast<char*>(am_pm[1]), const_cast<char*>(bp), 2) == 0)
		{
			if (tm->tm_hour > 11)
				return (0);

			tm->tm_hour += 12;
			bp += strlen(am_pm[1]);
			break;
		}

		/* Nothing matched. */
		return (0);

	case 'S': /* The seconds. */
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &tm->tm_sec, 0, 61)))
			return (0);
		break;

	case 'U': /* The week of year, beginning on sunday. */
	case 'W': /* The week of year, beginning on monday. */
		LEGAL_ALT(ALT_O);
		/*
		* XXX This is bogus, as we can not assume any valid
		* information present in the tm structure at this
		* point to calculate a real value, so just check the
		* range for now.
		*/
		if (!(conv_num(&bp, &i, 0, 53)))
			return (0);
		break;

	case 'w': /* The day of week, beginning on sunday. */
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &tm->tm_wday, 0, 6)))
			return (0);
		break;

	case 'Y': /* The year. */
		LEGAL_ALT(ALT_E);
		if (!(conv_num(&bp, &i, 0, 9999)))
			return (0);

		tm->tm_year = i - TM_YEAR_BASE;
		break;

	case 'y': /* The year within 100 years of the epoch. */
		LEGAL_ALT(ALT_E | ALT_O);
		if (!(conv_num(&bp, &i, 0, 99)))
			return (0);

		if (split_year)
		{
			tm->tm_year = ((tm->tm_year / 100) * 100) + i;
			break;
		}
		split_year = 1;
		if (i <= 68)
			tm->tm_year = i + 2000 - TM_YEAR_BASE;
		else
			tm->tm_year = i + 1900 - TM_YEAR_BASE;
		break;

		/*
		* Miscellaneous conversions.
		*/
	case 'n': /* Any kind of white-space. */
	case 't':
		LEGAL_ALT(0);
		while (isspace(*bp))
			bp++;
		break;


	default: /* Unknown/unsupported conversion. */
		return (0);
	}


	}

	/* LINTED functional specification */
	return ((char *)bp);
}


static int conv_num(const char **buf, int *dest, int llim, int ulim)
{
	int result = 0;

	/* The limit also determines the number of valid digits. */
	int rulim = ulim;

	if (**buf < '0' || **buf > '9')
		return (0);

	do {
		result *= 10;
		result += *(*buf)++ - '0';
		rulim /= 10;
	} while ((result * 10 <= ulim) && rulim && **buf >= '0' && **buf <= '9');

	if (result < llim || result > ulim)
		return (0);

	*dest = result;
	return (1);
}

int strncasecmp(char *s1, char *s2, size_t n)
{
	if (n == 0)
		return 0;

	while (n-- != 0 && tolower(*s1) == tolower(*s2))
	{
		if (n == 0 || *s1 == '\0' || *s2 == '\0')
			break;
		s1++;
		s2++;
	}

	return tolower(*(unsigned char *)s1) - tolower(*(unsigned char *)s2);
}

